I’ve recently noticed a lot of blog comment spam on my blog.
Where some-one kisses-bum in order to “trick” me into accepting their comment.
For example:
Howdy there,this is Everett Krajcer,just discovered your web-site on google and i must say this blog is great.may I share some of the Post found in this website to my local friends?i’m not sure and what you think?anyway,Many thanks!
Complete with a nice back link to his crappy website about “low rate loans”
This black hat SEO tactic is become very widespread.
Simply google a few phrases from that comment
Whilst you will not see any exact matches, they’re all along the same sort of lines, and on blogs…
The software posting these comments alters it very slightly for each blog posting, to fool search engines. 
To combat this, I’ve installed the reCaptcha plugin onto WordPress
Installation took literally two minutes, and is now up and running.
Apologies to any genuine comment posters, but the spam was becoming too much!
You can get the plugin here: